Relationship between tissue pO2 and chemoreceptor activity of the carotid body in vitro

Tissue pO₂ (pgO₂) and sinus nerve activity were recorded in the carotid body in vitro under hypoxic conditions produced either by interrupting the superfusion flow or by lowering the pO₂ of the medium (pmO₂). The pgO₂ gradient is the steeper the higher pmO₂ is. These findings point to a pO₂-dependent oxygen consumption. Under hypoxia produced by interrupting the superfusion flow, pgO₂ declines slowly down to final values and, concomitantly, the chemoreceptor discharge increases. Under hypoxia produced by lowering pmO₂, pgO₂ decreases rapidly down to values of about 3 torr, whereas the chemoreceptor discharge at first increases and then decreases, in spite of a maintained low pgO₂. The pO₂ threshold where the chemoreceptor starts firing under hypoxia, varies between 9 and 90 torr.     

Copolymers obtained by means of anionic ring-opening polymerization. Poly(2,2-dimethyltrimethylene carbonate-tapered-ϵ-caprolactone)

The anionic ring-opening polymerization of mixtures of 2,2-dimethyltrimethylene carbonate and ?-caprolactone in toluene as solvent, with sec-butyllithium or potassium dihydronaphthylide as initiator, results in the formation of polymers of the (A-X-B)_n type, where A represents a poly(2,2-dimethyltrimethylene carbonate) block, B represents a poly(?-caprolactone) block and X stands for a block of the two monomers with a composition gradient; n represents the number of portions by which the monomer mixture is added to the initiator or the living system. From the time-conversion curves it follows that the reactivity of the carbonate monomer is higher than that of the lactone. This difference in reactivity of the monomers is the reason for the special polymer architecture represented by (A-X-B)_n. The properties of these polymers depend upon the ratio of the monomers and the number n of additions. The polymers are characterized by spectroscopic, thermoanalytical, and thermomechanical measurements.     

Importance of the Duodenal Passage and Pouch Volume after Total Gastrectomy and Reconstruction with the Ulm Pouch: Prospective Randomized Clinical Study

p < 0.01), higher body weight, and better physiologic regulation of gastrointestinal hormones; moreover, they developed (in contrast to all other reconstruction types) no pathologic glucose tolerance. Our conclusion is that all patients with a postoperative life expectancy of at least 6 months (i.e., tumor stages UICC I and II) should undergo pouch reconstruction with preservation of the duodenal passage.     

Magnetic Resonance Imaging and Spectroscopy Findings After Focal Status Epilepticus

Summary: The etiology of cerebral abnormalities after focal status epilepticus (SE) is unknown. Possible causes include hypoxia and the excessive release of excitatory amino acids. Magnetic resonance imaging (MRI) of a 21–year-old patient with "cryptogenic" continuous motor seizures showed swelling and signal hyperintensity of the contralateral panetotemporal cortex, the thalamus, and the ipsilateral cerebellum on T₂-weighted images. These regions are connected by glutamatergic pathways. Proton magnetic resonance spectroscopy (MRS) of the cortical lesion yielded a signal peak at the resonance frequency of 2.29 ppm, suggesting a focal increase of glutamate or its degradation product glutamine. At 3–month follow-up, structural alterations had disappeared, but the N-acetylaspartatelcholine ratio was still reduced in the previously abnormal area. These findings are the first to demonstrate the contribution of MRS to pathophysiologic studies of focal SE in humans and, in combination with the pattern of imaging abnormalities, support a major role of glutamate for seizure-related brain damage.     

Aminoalcohol esters of hydroxyboranes. 10. Tetracycline boron Mannich bases as potential antineoplastic agents

Aminoalcohol Esters of Hydroxyboranes, X: Boron Mannich Bases of Tetracycline: Potential Antitumor Agents The synthesis of the boron-containing N-Mannich bases 1 of tetracycline, paraformaldehyde and boron-heterocycles is reported. The condensation product 2 of phenylboronic acid with tetracycline is described. Compound 1b may show some activity against Leukemia P388.     

Über die freie und die gebundene zentralnervöse Hemmungssubstanz der Wirbeltiere

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